user
Outline an algorithm to solve the "8-puzzle" game.


assistant
The 8-puzzle is a sliding puzzle that requires the player to slide numbered tiles into a 3x3 grid to complete the puzzle. The algorithm for solving this puzzle includes a breadth-first search technique. This involves creating a list of nodes that contains the puzzle’s current state (position and order of squares) as well as previous states (to minimize searching duplicate states). The algorithm then proceeds to move each tile to the blank space and evaluate if the resulting new state is a goal node (i.e. end of the puzzle). If it is not, the program moves on to the next node, keeping track of the nodes already visited and continuously recording the new states for further evaluation. Once the goal node is identified, the program calculates the optimal path from the start node to the goal node.